Composition for cleaning aluminum



x agent. More particularly, it relates to a nonabrasive acid cleaning-composition which may bepackagedinfdry I 1 actions are known in. the art, most of them are liquid in form. For that reason, they require substances; these containers may be-broken dur- 1 ing shipping or handling, and. great damage may ovensuch liquid". acid compositions occupy substantial storing space.

.novel cleaning] composition in dry or solid form mciflc' object of: the invention is to provide a- 1 non-abrasive" cleaning composition which may be packaged in'dry formand used in an aqueous or aluminum alloyarticles. Other objects will appear in the following d'escription'of the invention., A

are very readily removed from the surfaces 'ot ous solution containing an alkali metal acid phosphate in suitable concentration, depending upon the nature of thearticlesbeing cleaned.

v These phosphates are all solid and may be packaged in powdered or in granular form .until ready for use. Then, slncethey are all water-soluble, v

they may be dissolvedin water at a temperature near its boiling point to provide a cleaning medium whichissufllciently acid in reaction to be 'metal phosphates having an acidreaction are "effective for cleaning tarnished surfaces of alumlnum articles, we prefer to use ammonium diclassification of an'alkali metal acid phos-1 ily available, and it appears to be morev strongly Patented n" UiNiTEb STATE the surfacesof the articles being cleaned. The alkali metal acid phosphates have particular Q value in'the cleanln'g of aluminum or its alloys,

and are particularly effective in "removingdis-g colorations from the surfaces of aluminum kitchen utensils, barrels/dairy equipment and :other, articles of aluminumor aluminum alloy.

i s PATENT {O FICE co munes FOR CLEANINGALUMINUM Robert H. Brown, New. Kensington, and Robert B. Mears, Oakmont, Pa., assignors to Aluminum Company of America, Pittsburgh, Pa.,,a corporation Pennsylvania 1N0 mung. Application April 22,193

seri morzcsass H f "4 cums. (chase-13c acid than the other alkali metal acid phosphates. f While all of the alkali metal acid phosphates are, individuallysuillciently active to remove dis- .coloration from'the surfaces of aluminum and 1 other articles, it may be desired to increase their effectiveness in this respect. This may be done by using with them; an additional substance i This invention relates to an improved cleaning form and dissolved in water for use.

While cleanin aqueous alkali phosphate. solution. Th additional substance also should besolid in form in order that it may be packaged with the alkali phosphate, and it should be soluble in water so that it maybe dissolved in the aqueous phosphate solution. We prefer to use an alkali metal 7 acid sulfate, such as ammonium bisulfate, as a the additional acid substance; other acids or acid salts also may be used to advantage, among them being metaphosphoric acid, sulfamic acid, and.

careful handling and must be packaged in the more expensive containersdesignedto. hold such 10 then be caused by their acid contents. More- The object of this invention is to provide a which may easily be handled and packaged. More particularlyptheobject is to provide such a compositionhaving an acid reaction. The spebeing especially effective, A cleaning composition containing an alkali metal acid phosphate and sulfamic acid is claimed in our copending application Serial No. 269,490, filed April 22.

1939. In addition, we have found that tartaric acid may be used with this additional substance where it is desirable that the cleaning solution should work with even greater effect. Tartarlc acid also is solid and water-soluble, and may be .packaged in dryflform, with the alkali metal solution for, cleaning the surfaces of aluminum Wehave found that stains and discolorations articlesby immersing said articles in a hot aquenamed:

. Instead of using a substance with the alkali metalacid phosphate which increases the acidity of the solution, the additional solid, water-soluble substance may be a neutral compound capable of dissolving in the-aqueous phosphate solution and reacting in water to form an acid which will etch the particular material being effective, yet not so lviolent as to attackand mar minum, sodium fluorid in the phosphate cleaning composition dissolves in water to form hydrofluoric acid,.which supplements the cleaning effectof the acid phosphate.

The addition of wettingagents, such asycer- I "ence with a smaller amountofphosphate and Although sodium, potassium, and other alkali,

5o by-the nature of the object being cleaned.

hydrogenphosphate, which is included in the phate. 'Thiscompoundis inexpensive and readadapted to increase the acidreaction of, the

1 the alkali metal fluorides, ammonium bifluoride phosphate and any of the substances above cleaned. For example, in the cleaning of alutain of the alkyl sulfonates, also may, be profitable, since cleaning may be efiected in their presadditional substances in the solution. The par-. ticular wetting agent used should be determined" In the practice of one embodiment'of the in- I vention, we have used 25 grams of ammonium dihydrogen phosphate and 25 grams of ammonium bisulfate dissolved in one liter of water, the solution being heated tonear C. This solumetal, it may be employed for cleaning other materials as well.

We claim: I 1. A process for cleaning the surfaces of articles of aluminum, which comprises subjecting said surfaces to the action of a hot aqueous solu tion of a composition consisting substantially of an alkali metal fluoride and ammonium dihydrogen phosphate, the latter being the major component and the principal active cleansing.

agent.

2. A dry water-soluble aluminum-surface being characterized by an acidic cleansing reaccleanser for use in aqueous solution, said cleanser being characterized by an acidic cleansing reaction in said solution and consisting substantially of an alkali metal fluoride and ammonium dihydrogen phosphate, the latter being the major component and the principal active cleansing agent. 7 Y

3. A dry water-soluble aluminum surface cleanser for use in aqueous solution, said cleanser being characterized by an acidic cleansing reaction in said solution and consisting substantially of sodium fluoride and ammonium dihydrogen phosphate, the latter being the major component and the principal active cleansing agent.

4. A dry water-soluble cleanser for use in aqueous solution, said cleanser tion in said solution and consisting substantially of an alkali metal fluoride and an alkali metal acid phosphate, the latter being the major component and the principal active cleansingagent. ROBERT H. BROWN.

ROBERT B. MEARS.

aluminum-surface 

